Speed controlled brake



2 Smets-sheet 1 E. E. HEWITT SPEED CONTROLLED BRAKE Filed June 30, 1936 G uli Jombzoo .Vl

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Dec. 20, 1938. V'E E HEW|TT I 2,140,624

SPEED CONTROLLED BRAKE Filed June 30, 1936 2 Sheets-Sheet 2 65 368,36? se@ 364 se? Ti@ f2 4 @a INVEN'roR ELLIS EHEWITT Qff.

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ATTORNEY irl-:D lSTATES Paten-ted Dec. 20, 1938 PATENT OFFICE y ,'KV'I'hisinvention relatesoto brake equipments or Y systems for vehicles-such as high speedrailway cars lor trains, which'equip'ments or. systemsare vadaptedto automatically control the brake cylinvj'5, der' pressurethebraking. fo'rceand the braking ratiofaccording to the speed of the car or train.

` .Y As is welllknown, the ,coeicient o firiction be- 4Ytwee'n the 'brake shoesand the car wheels be- ;comes greater for the lower speedso'f travel and,

' l0 conversely, that the coeflicient of friction between y th'e brake shoes and the car wheels becomes lower 'for thehigh'er speeds offtravel. In order, theresfere,L to prevent the application of the brake shoes to the car wheels with such excessivev force at the f airs -igwer speeds 'of travel that sliding of the wheels would be caused due to the exceeding of the co- Vfjeiicient of adhesion between` the car wheels and ,f the track rails, Avarious devices and systems have o ,been devised for automatically reducing the brake 1220v Vcylinder pressure and consequently the braking jiforce so as to preventY sliding of the wheels.

' :Among thevarious types of such devicesor systems;y are" Vthose including an `inertia operated ,Y device or `retardation controller which is auto- ,.(325 matically effective according to the rate of retardation of a car ortrain to cause such reduc- "tiongin' the brake cylinder pressure while the car or trainl is decelerating under the lapplication of i 1 "the .brakes that the rate of retardation of the car sofor trainis regulated to ai'substantially uniform rate. j

o i In my'copending application Serial No.741,063, "filed August 23, 1934, land assigned tothe asfsignee of the'present application, there is shown 3:1 and described a'combination straightairand auftomaticbrake system yemploying anV inertia op erated' device or retardation controller for kcon- Y f :trollingthe brake cylinder pressure so as to prej vent sliding of the wheels.v

140 In; embodying my invention in practical form,"k

it is my'y intention to provide a brake system of `Veither, the straight-air or. automatic type orY a sysl 'temllaving both straight-air; and automatic opferatio'n, as in systems of the character shown and rdescribedin the copending application referred to,ftlie,retardation controller or the said copendn ing; application being replaced however by a relay o o aor control 'valve device "of novel constructionA f '@'Whichl is controlled'automaticallyy according to '50"'the speed of the-car ortrainto cause variations loffthebrake cylinder -pressurein aseriesof steps l `v fias*thes'peed ofthe carfortrainreduces inzbeing ,brought to a-stop. Thusin my present inveni y'-tiongthe brake cylinder pressure 'or braking force x55 fisdecreased automaticallyfromthehigher presrn the @pending application, serieu No. 40,902, led September 17, 1935, of which I am joint apsures or forces eiective at the higher speeds to -lower pressures or forces at the lower speeds in order to prevent sliding of the car wheels at the lower speeds.

plicant with Clyde C. Farmer and in the copend- Afing 'application Serial No. 66,234, filed January 28, 1936,r of John W. Logan, Jr., both of which applications are assigned to the assignee of the 10 v present application, there are disclosed' various types of brakesystems wherein speed responsive devices are employed to effect reduction in brake cylinder pressure' automaticallyiupon a reduction in the speedof travel of the car or train. How- 15 ever, in both of the applications just mentioned, konly oneautomaticreduction in brake cylinder pressure from the highest initial brake cylinder pressure is reffected during an application of the fbrakes and this one reduction occurs only when '20 the speed of the car or train reduces below a krelatively low uniform speed, such as fifteen or twenty miles per hour. In my present invention.

I propose to provide brake equipments including lnovel controlv valve devices operative according k25 to the speed of travel of the car or train to automatically elect agraduated reduction, that is, re-

duction in a series of steps, of brake cylinder vpressure, from the highest pressure in the brake cylinderat the time an application of the brakes 30 is initiated without necessitating any manual operation by an operator. Furthermore the novel control devices, which I provide, so regulate the rate of change of brake cylinder pressure in passing from one pressure step to a lower pressure 35 Astep that the change in brake cylinder pressure does ynot take place abruptly but rather in a lgradual manner so as'to prevent shocks and jars to the car rand the consequent discomfortto the passengers. f 140 In general, therefore, it is an object of my pres- !ent invention to provide a brake equipment for high speedcars or trains, which equipment is of thefcharacter showny and described in the colp'ending4V application Serial No. 741,063, above re- -l5 'ferred to, wherein `the automatic control of the brake cylinder pressure or braking force to pre- 'vvent sliding of the wheels is efectedaccording to thespeed of thecar or train.

'It' is another object of 4my invention to pro- 50 Vide a'brake system of the-character indicated in the foregoingv object and including novel control devices andarrangements for automatically "causing 'different brakelcylinder pressures, that is y 'brakingratios to be effective at the time an 'application of the brakes is initiated, dependent upon the speed of the car or train at the time the application of the. brakes is initiated.

Another object of my invention is to provide a brake system of the character indicated in the foregoing object wherein the novel control devices and arrangements for determining the brake cylinder pressure or braking ratio at the time an application of the brakes is initiated also operates automatically to reduce the brake cylinder pressure or braking ratio in a series of steps as the speed of the car or train reduces under the application of the brakes.

Another object of my invention is to provide, in a brake system of the character indicated in the foregoing objects, a novel control valve device, which is controlled automatically according to the speed of travel of the car or train, yto eiect reduction in a secondary control pipe pressure, which controls brake cylinder pressure, to

pressures having uniform and successively decreasing ratios withr a given fixed primary control pipe pressure, Vas the speed of the car reduces under the application of the brakes.

1 A'further object of my invention is to provide a control valve device of the character indicated 4in the foregoing object which is adapted upon applications of the brakes at below a certain low speed of travel of the carto cause the pressure in :the secondary control pipe and accordingly in the brake cylinder to be built up substantially equally with the pressure in thel primary control pipe until such time as the brake shoes contact the car wheels, and thereafter to cause the secondary control pipe pressure to bear lessthan a one to one ratio to the primary control pipe pressure.

Another object of my invention is to provide a control valve device of the character indicated .1in the foregoing objects, which enables rapid adjustment of the secondary control pipepressure in correspondence to a reduction in the primary control pipe pressure.

The above objects, andother objects of .my invention which will be made apparent subsequently, are attained by means of several simplied illustrative embodiments described hereinafter and shown in the accompanying drawings wherein, i

Fig. -1 is a simplied view of the essential elements of a brake system embodying my invention, showing one type of novel control device,

fFig. 2 is a fragmentary sectional view showing a modified type of control device,

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2,

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2, and

Fig. 5 a view showing the lock washer of Fig. 4 in detail.

Referring to Fig. l, the brake equipment shown is for one car and is illustrative of similar equipment on other cars in a train. The equipment for 'one car may comprise a main reservoir 6, a brake vcylinder l, a self-lapping brake control valve devaccording tov the speed of travel of the car or train, a speed responsive or governor switch device ID for controlling the magnet valve devices.

of the control valve device 9, a pneumatic switch device II, and a source of electrical energy indi- :cated as a storage battery I2.

, Considering the various parts of the equipment `.now in further detail, the self-lapping brake conendthereof the stem 3870i the piston I9. kouter end of the bore 29 is threaded to receive a trol valve device 8 comprises a casing section I4 having formed therein a suitable pressure chamber I5 open at oneA end, a casing section I6 secured to the casing section I4 to close the open end ofthe chamber I5 and a pipe bracket section II secured to the section I4.

The section I6 contains a bore I8 having a piston I9 therein, the piston being yieldingly urged toward the chamber I5 in the section I4 by a biasing spring 2| interposed in the bore I8 between one face of the piston I9 and an adjusting `screw 22 threaded into the outer end of the bore I8. The piston I9 is provided with a chamber 23 which is open to the chamber I5 through a passage 24 in the piston and which is also open to a chamber25 at the opposite side of the piston to the chamber I5 through a bore 26 and a pair of branch passages 21. Contained in the chamber 23 is a release valve 28 shown as a pin valve which is `normally unseated from its associated valve seat surroundingthe bore 26 by a vcoil spring 29, the spring 29 being interposed in a bore 3I in the face of the piston I9 which isvopen to the chamber I 5 between the wall of the piston and a ange Yorcollar 32 on the valver28. A washer or collar 351s removably secured to the face of the piston Vand is provided with a central opening through which the end of the Valve extends, the washer 33 serving as a stop to be engaged by the flange 32 on the valve 28 to limit the unseating movementl of the valve 28 from its valve seat. The chamber .25 at the right of the piston I9 is constantlyopen to atmosphere through an exhaust port and passage 34.

The casing'section I6 is alsofprovided with a chamber 3l which is constantly connected to the main reservoir 6 through a passage and pipe 38 and a branch pipe 39, the chamber 3l containing a supply valve 4I which is yieldingly urged by a spring 42, interposed between the valve and the inner face of a cap screw threaded into the casing section, into seated relation on an associated valve seat to close a supply port l44 in the wall of the casing section I6 connecting the chambers I5 kand 31.

thereof an operating handle 4'! secured thereto in the usual manner and an operating cam 48 secured to the shaft 46 within the chamber I5. The face of the cam 48 engages the end of a plunger 49 slidably mounted in a bore 5I in the inner face of the casing section `II and openingk linto the chamber I5, the plunger 49 carrying a Ylioating lever 52 which is pivotally secured intermediatefthe ends thereof by a pin 53 extending through the plunger 49. Suitably mounted at one end of the lever 52 is a roller 54 which is @adapted to engage the end of the release valve 28 ,projecting intothe chamber I5, the opposite end of the lever 52 having one end a stem or rod 56 pivotally secured thereto as by a pin 5T, the opposite end of the stem extending through the port 44 and engaging a suitable recess at the inner seated area of the supply valve 4I.

The adjusting screw 22 is provided with a central boreZU for slidably receiving at the inner The screw 4U, and a lock nut 5B is provided for lockiing the screw 4i) inplace. f .-The biasing spring 2.9 of the release valve 28 is l.relatively lightly tensioned while the biasing spring 42 lfor thesupply va1ve'4l is more strongly i'tensioned. This biasingsprlng 2| for the piston I9 isA more' strongly-tensioned than the spring42 randthe tension thereof 'may be adjusted as de- Ysired' by turning the adjustingV screw 22. Y The #purpose of* the varying 'spring tensions and strengths Vwill appear presently. Y

C When theoperating Vhandle 41 of the control fvalve device 8 is rotated from ,release` position Vintctheapplication zone, the cam 48 on the shaftr 46 `causes movement of theplunger v49 inwardly "fof-'the bore 5I.- YSince, the spring 42 iis. strongery `than ltheV springv 29,' inward ,movement of the z plunger49, as just described, causes pivotal mover'ment ofthe lever 52 on the pin -51 as a fulcrum, f VVthe end of the lever 52 carrying the roller 54 being thus moved in a counterclockwise direction f toseat the release lva1ve23'on its associated valve f Yseat to close the communication between the '34.* When the releasevalve 28`is seated, Vthe chamber I and the atmospheric exhaust passage yfgbia'sing spring 2I acting on the piston I9 prevents further movement of the end ofthe lever 52 car- Trying Vthe roller 54 andconsequentlythe lever 52 VVVis' thereafterk pivotally moved-ima clockwise di- '7 frection, with the axis ofthe'roller 54 `as ya fulcrum,

. "tito thereby cause movement of the operatingstem Y f ."Eifin the right-hand. direction to. overcome the *i .,biasingspringr42 and unseatv the Vsupply'valve 4I. 30

Fluid under pressure isfthus supplied from the vmain reservoir. and ythe supplyr lchamber 31 through the vport/44 tothe pressurelchamber I5.

V,When the pressure inthe chamber I5'in'creases ff 4o l application zone, cam 48 causes furtherr inward `movementfof the plunger 49, thesupply valve` 4I being lthereby again' unseated; to again supply c y sufliciently to move the piston 'I 9 against theforce :ofthe biasing spring 2Ithe biasing spring 42 for Y Lthesupply yvalve 4I .becomes effective to reseatV supply valve 4I and cut off further supply of fluid .under ypressure .toV the 'chamber I5. v If the operatingv handle 41 is rotatedV toa furtherextent away from release position into the :fluid under pressure from'r themain reservoir 6 zandfsupply chamber 31 to the chamber I5 until such timeas the pressure in the chamber I5 is sufficient to move the ypiston I9 intheright-hand direction againstthe ,force of the spring 2| and 4, thus permit reseating rof the 'supply valve 4 I.

The maximumpressure attainable in the chamber'. I5 is determined by the adjustment of the @screw 40 which limits the movement ofthe pis-l ,ton I9 in the right-hand direction, for obviously V if the piston I9`is prevented from moving in the right-hand direction in response to thel pressure jinV thechamber `I5 acting thereon, the supply 'E valve 4I cannot be reseated andconsequently the Q vfull pressure of the mainreservoir becomes effecv l VftiveY in .the chamberV I5.

. toward release position from application position,

fthe forcefon' the'lever 52 holding the release valve 28 seated is relieved and thek spring 29` thus rbe- Acomes effective to unseat vthe release kvalve to open Acommunication'for; the exhaust of .fluid y-Junder pressure from the chamber I5 through the *When the operating zhandle 41 is; Vreturned .vpassage24, Achamber 23,y port ,26, passages 21, v.chamber 25-and exhaust passage 34. Whenv the pressure of the fluid inthe chamber I5 isrejbgduced sufficiently, the biasing spring 2| acting on the piston I9 moves the piston in the lefthand difrectionand since theroller' 54 carried on the lever r'52. isfheldin position by the hand ofthe opje'ratorjv'vhich holds the operatingvhandle in posi.

ation andther'ebyprevents inwardmovement cf thevalve 28, the piston I9 carrying the valve seat for the valve 28 is moved into engagement with the valve 28 to close the exhaust communication for the chamber I5 to prevent further reduction Y'in the pressure of the fluid therein; When the operating handle 41 is returned a further degree ktoward release position, the release valve 28 is again unseated to cause fluid under pressure to be exhausted from chamber I5 through the exhaust passage 34 until such timeas the spring 2I becom'es electiveto again reseat the. valve 28 to close off the exhaust communication.

When the'handle 41 is returned into release position, the spring 2I is ineffective to cause reseating of the valve 28, and the valve 28 accordingly lremains unseated Vas shown in Fig. 1 to cause the complete venting of fluid under pressure from the chamber I5 to atmosphere through the exhaust port 34.

It will thus be observed that the pressure in rthe Achamber I5 isl at all times proportional to the position of theoperating handle 41 in the application zone with respect to the release position.

' The control valve device 9 which constitutes a particular featureof my invention, may comprise la casing having arelay valve section 6I, a plurality ofv diaphragm'clamping sections 62, and a magnet valve section 63. Associated with the casing of the control valve device 9 is a casing 64 in which are formed a plurality of timing reservoirs 65, 66 and 61, the casing 64 being optionally formed as a Vseparate unit, as shown, vor integrally Y secured to and forming a part of the casing of the control device 9.

' The casing section 6I of the control valve device 9 has formed therein a chamberA 68 which is constantly supplied with fluid under pressure from the main reservoir 6 at a pressure regulated by a feed .valve device 69 of well known construction Vthrough a pipe 1I, hereinafter designated 'the ,suitable control equipment, such as shown in my copending application ySerial No. 741,063 referred to above and intervening in the control pipe between the retardation controller shown therein and the brake cylinder, also intervene, in the present instance, in the secondary control pipe 11 kbetween the control valve device 9 and the brake cylinder 1.

For the purpose of controlling communication between the chamber 68 and the chamber 14 Ythrough port 80and for controlling communica.-

tion between the chamber 14 and an atmospheric exhaust port or passage 19, a supply valve 8| and a release valve 82 are respectively provided. The supply valve 8I may be in the form of a piston valve slidably mounted in the bore 84 ina cap screw 85 which closes the chamber 68, a biasing or return spring 86 being interposed between the cap screw 85 and the rear face of the valve 8I to yieldingly urge it into seated engagement on an annular rib seat 81 surrounding the passage 80 connecting the chambers 68 and 14. The valve 8| is providedwith a projecting stem 88which extends through the passage 80 into-the chamber 114.andwhich is adapted to be engaged Ybythe Aend :of a valve-operating stemf09 in the :manner `which will appear presently. `rOne .or more ports 9| are provided in the valve 8| in order tor` prevent dash-.pot action of the valve v8| in the bore .84 of the cap screw 85 and for equalizing the uid pressure on opposite sides of the valve.

The release slide valve 82 slides on a suitable seat face 92 and is loosely engaged in a suitable recess 93 in the valve operating stem 89.

When the valve operating stem 89 is moved in the left-hand direction, the release slide valve 82 is first moved to close ycommunication between the chamber 'I4 land the atmospheric exhaustport 'I9 and then the left-hand end of the operating `stem 89 engages the projecting stem88 on the supply valve and unseatsthe valve 8| against `the force of the spring 86 to open communication for Ythe supply of fluid under pressure from the feed Valve pipe 7| and the chamber 68 to the chamber 'M and the secondary control pipe When .the operating stem 89 is moved in the right-hand direction, the operating stem 89 first disengages the stem 88 of the supply valve 8| so that itis reseated by the spring 86 to cut ofi communication `between the chambers 68 and iments or diaphragms 95, 96,91 and 98,'of successivelydecreasing .pressure areas in-the order named.

The diaphragms95, 9.6, 91 and 98 are suitably `mounted in spaced coaxial relation by means of the clamping sections 62 and in such relation to the casing section 6| that the common axis .thereof is coincident with the axis of the operating stem 89. A plurality of spacing members 99 of spool shape and varying size are disposed, one between each pair of successive diaphragms,

Vand cooperate to secure the diaphragms together .for simultaneousmovemena the right-hand end of the operating lstem 89 having a fiange :|0I Which cooperates with oneof the anges on one of the spacing members 99 to secure the diaphragm 95 therebetween. It will thus be seen that the operating stem 89, in eect, .has all of the diaphragms 95, 96, '91 and'98 secured thereto.

' In orderto supportthe operating stem 89 and relieve the diaphragms 95,296,791 and `90 of the weight o f the operating stem. 89 and of the spacing members 99, the operating stem 89 is provided with a guiding and supporting piston |02 which operates in a bore |00 in therelay valve casing section 6I and hasat one si-de thereof the chamber 'I4 and at the opposite side thereof a chamber |99 to which the left-hand face of the diaphragm V95 is open. The piston |02 has a port or passage |03 therein for connecting chambers'M and |04. A rod or shaft |05 is also provided to support the opposite end of the stack of .diaphragms, which rodis secured to the smallest of the diaphragms 98 and which operates slidably in a bore |06 formed in the end casing section 62.

Formed between the'largest diaphragm 95 and ythe adjacent smaller diaphragm 96 is a chamber 1115 adjacent .smaller Vdiaphragm9`| is a'. chamber IIB which .is lin constant ,communication with the ,timing chamber 66 through a passage and pipe |08. Formed between the diaphragm 91 and the smallest of the diaphragms 98 is a chamber III which yis in constant communication with the timing chamber 61 Vthrough a passage and pipe |09. It Will beV understood that the volume or capacity Vof the chambers 65, 66 Aand 61 is relatively large that the pressure in chamber I|8 of the control valve device `9 .is always the same as the pressure 'in the pressure chamber |5 of the brake control device. .8.

A ,plurality of magnet Valve devices I 25, |26

and I2.'I, .embodied'in the magnet valve casing? section 63 are provided for controlling the communication between the-primary control pipe 'Ila and chambers II5, I|6.and,| II, respectively, and also for controlling communication through which iuid under pressure is `.vented toatrnosphere from the chambers H15, I |6-and I|'|, respectively.

The magnet `valve device |25, hereinafter designatedthe high speed magnet valve device, comprises a pair of oppositely seating valves II9 and |20 connected by a luted stem |2|` and adapted to be operated by an electromagnet Winding |22 through the medium of -a plunger rod erstem |23. .The valve H9, hereinafter called `a supply valve, is contained in achamber I29of casing section v63, which chamber |29 is constantly connected to the passage III and thus to the primary. control pipe Ha, and the valve 20, hereinafter called the release valve, is contained in a chamber I.3|

Ywhich is constantly open to atmosphere through A chamber |34, `disposed between the chambers |29 and |3| and through which the fluted stem |2| connecting the a passage |32 anda choke |33.

supply andrelease valves I I9 and' |20 exten-ds, is constantly connected tothe passage |01 leading Ato the chambers I I5 and 65 by a branch passage.`

|35. When the electromagnet Winding|22 is energized, the valves and I|9 areaccordingly simultaneously moved into seated and unseated positions, respectively, against the force of a biasing spring |36 contained in chamber |29. Spring 4|36 is effective toyieldingly urge the valves ||9 and |20 into seated and unseated positions, re- "spectively, when the electromagnet winding |22 is deenergized. It will thus be apparent that when the electromagnet Winding |22 is energized, communication is opened for the supply of uid under pressure from the primary control pipe 17a, past the-unseated supply vkvalve ||9 into the -chamber |34 `and thence to the chambers I|5 and 85. It will also be apparent that when the electromagnet |22 is deenergized, the timing -chamber 65 and the diaphragm chamber ||5 are vented to atmosphere past the unseated release valve |20 and through the choke |33.

The magnet valve device |26, hereinafter designated the intermediate speed magnet valve device, is identical in construction to the magnet vvalve device and comprises a pair of oppo- :sitely seating. supply andrelease valves |39 and .|40 which .are .connected by ,theutedstem I 4| The smallest chamber |49 which is constantly connected to 5f `thepassage through a'branch passage |50V fand .thek release valve |40 is contained in a-chamr-berf|5| 'which is constantly open to atmosphere through ar passage |52;- containing a, choke |53.

' '-Disposen between the chambers |49 and |751 is a l chamber |44gthrcugh which 'extends the iluted Y 1 istemg|4|l connecting the supply and release'valves f V|39 and |40, the chamber |44 vbeingconstantly .connected to the passage |08 leading to the jydiaphragm chamber I6 and the timing chamber` 15V v66 by abranch passage |45. Energization of the electromagnet l|42 causes the valves |39 and |40 tor be actuated to unseated and seated positions, respectively, against the force'of a biasing spring y|46 contained inthe chamber |49. Spring |46 20. iseffective tov yiel-dingly urge the valves |39'and |40r into seated and unseated positions, respectively, when" the electromagnet winding |42 is deenergized. It will thusbe apparent that when theelectromagnet winding V|42 ofthe intermedi#` `25i ate' speed magnet valverdevice |26 is energized,

-' `cornrnunication is establishedr through which uid f under pressure maybe supplied vfrom the primary control pipe 11a and passage to the passage |08` leadingto the diaphragm'.` chamber I6 andk 30``the timing chamber 66. It will also be apparent that when the electromagnet winding |42 of the Y magnet Valve device V |26v is deenergized, com- I Y Qmunic'ation is established through which the diaphragm chamber ||6 andthe connectedv timing 95 chamber 66 are vented to atmosphere pastthe uns'eated release valveV |40A and through the choke |53.

, The magnet valve devicer |21, hereinafter desig- 'innated the low speedmagnet valve device, comcio prises'y a 'double beat. valve |59 having a fiuted' stent-|69 on opposite sides thereof and operatedr .by/ani electromagnetlwinding |62 through the fl mediumofa plungerrod or stem |63adapted engage the endof the upper. iluted stem |60- .L ofthe! doublebeat valve |59. The ,valve |59 is contained in a chamber; |64 which is constantlyi '.,connected'through a'branch passage |65 to the passage |09 leading to the diaphragm chamberv ||1.V and the timing chamber 6 1. VWhen the elec- Y 501 tromagnet winding |62 is deenergized, the double .beatwvalvevl59 is actuated to anupperseated position by a biasing spring |66, acting on they fend ofthe lower flutedfstem |60, to establish communication between. the chamber |64 anda V 55, chamber .|61, which is constantly connected by a branch passage |6| to the passage and thus yto the primary control rpipe 11a.

n When the Y electromagnet winding |62- of the magnet valve 1 vdevice. |21 is energized, the double beat valve |59 (if), isr actuated to alower seatedlposition to close the *communication just described andfopen a communicationbetween theV chamber |64 and a cham- Y Qber.V |1| which is constantly connected to atmosphere through a-passage .|12 containinga choke y v 5" |13. It will thus be, apparent that when the velectrornlagnet winding|62 of the low speed magnetvalve device |21. is deenergized, communication isfestablished through which fluid under V`pressure may be supplied fromthe primary conis vented from the diaphragm chamber ||1 and` the timing chamber 61 to atmosphere through the choke |13.

The speed-responsive switch device |0 operates to control energization and deenergization of the magnet valve devices |25, |26 and |21. The speed-responsive switch device `|0 may be of any suitable construction and is illustrated as comprisinga casing |15 which is mounted in` any desired location on the body of the car and having a chamber |16 containing a centrifugally operated device |11 for actuating a switch device |18. The-centrifugally operated device |11 may comprise a rotary member |19 having a pair of projecting'yokes |8| on diametrically opposite sides thereof, only one prong of each yoke being shown, and arpair of bell crank levers |82 carried between the prongs of each yoke |8|, respectively, and pivotally mounted thereon by a pin |83. Each bell crank lever |82 carries a weight such as a ily-ball `|84 at the outer end.v thereof, the inner end thereof being 'adapted to engage the lower face of a collar |85 secured to the lower end of the operating stem |86 of the switch device |18, within the chamber |16. A shaft |81, suitably journaled in the casing |15, carries the rotary member |19 at the inner end thereof and is adapted to be rotated according toy the speed of travelof the car, either by connection to a car wheel axle or to the armature shaft of the usual generator carried on the car and driven from anA axle of the car. A

Secured in insulated relation to the upper part of the casing |15, which is broken away for clarity, are three pairs of contact ngers |9|, |92 and |93. 'Ihe operating stem 86 of the switch device |18 carries three contact members |94, |95 and |96 for engaging the pairs of contact fingers |9|, |92 and |93, respectively, in bridging or circuit-closing relation.

Interposed in the chamber |16 between the wall of the casing |15 vand the collar |85 secured to theA operating stem 86 of the switch device |18 is a biasing spring |91 which yieldingly urges theoperating stem |86 downwardly. The operat' ing stem |86 of the switch device |18.may be of metal with the contact bridging members |94, |95 and |96 suitably insulated therefrom. However, for simplicity, the operating stem |86 may be of insulating'material, as shown, so as to insulate the contact Vmembers |94, |95 and |96. The contact member |94 may be in the form of a strap .or disc secured to the upper end of the op- 1 erating shaft |86 by a nut |99. 'I'he contact members |95 and |96 are suitably mounted on the operating stem |96 for limited movement relative thereto. VThe contact members |95'and 96 may be either in the form of a strap Yor a disc having a central perforation throughwhich the' operating stem |86 extends and mounted on oppositevside's of a flange 20| carried on the stem |86.- A biasing spring 202, interposedbetween the flange 20| and the contact member |95, yieldingly urges the contact member |95 away from the 1iange20l, the contact member |95fbeing movable slidably along the operating stem and the extent of movement of the contact member |95'away from the ange 20| being limited by a stop flange-203 `carried on the stem |86. In a similarrmanner a coil spring 204 interposed between vthe opposite side of the flange 20| and theY contact member |96 yieldingly urges the contact member |96 slidably along the operating rod|86, the extent of movement of the contact member |96 away from the flange 20| 'being limwith the contact fingers |92'.

ited' by a stop liange 205 carried on the operatin stem |86. Y

Whenever the car is stopped and as. long as the speed of travel of the car is less than a certain uniform relatively low speed, such as fifteen miles per hour, the tension of the biasing spring |91 is vsuiiicient to actuate the operating stem |86 of the switch device |19 downwardly to effect disengagement of the contact member |94 from the contact fingers |9|, disengagement of the contact member |95 from the contact fingers |92 and engagement of the contact member |96 with the contact lingers |93. As the speed of travel of the car increases above the certain uniform low speed, such as fifteen miles per hour, the centrifugal force acting on'the weighted bell crank levers |62 overcomes the tension of the spring |91 and moves the operating stem |96 upwardly to effect disengagement of the contact member |96 from the contact fingers |93. The relation of the contact member |95 to the contact fingers |92 is such that engagement thereof is not effected until the speed of travel of they car exceeds an intermediate speed such as thirty-five miles per hour. The relation of the contact member |94 to contact fingers |9| is such that engagement thereof is not effected until the speed o1' travel of the car exceeds a certain uniform high speed, such as sixty miles per hour. It will be observed that when the operating stem |86 of the switch device |18 is actuated upwardly after the contact member |95 engages the contact fingers |92, the spring 292 yields to permit-further upward movement of the operating stem |86 to effect engagement of the contact member |94 with the contact lingers |9| ywithout imposing undue stress on the contact lingers |92.

As the car or train decreases' from a speed in excess of the certain uniform'high speed of, for example, sixty miles per hour, to a speed below the sixty miles per hour, the spring |91 becomes effective to urge the stem |86 downwardly to effect disengagement of the contact member |94 from'the contact fingers I9 I. It will be observed,

however, that since the spring 202 acting on they contact member |95r has been compressed the contact member |95 continues in engagement When the speed of travel of the car has reduced to the certain uniform intermediate spee-d of thirty-five miles per hour, suiiicient downward movement of the operating stem |86 has been effected that the speed of, for example, fifteen miles per hour is reached. As the speed of travel of the car decreases below the uniform low speed of fifteen v miles per hour, the. biasing spring |91 is effective tofurge the operating stem |86 still further downwardly in opposition. to the centrifugal force acting on the bell crank levers |82 Y so that the spring 204' is yieldinglycompressed, thus effecting 'good' contact engagement between the contact member |96 and the contact fingers |93 and preventing the exertion of undue stress on the contact fingersY |93.

summarizing, as to the speed-responsive switch devicev I0, the contact member |96 only is in circuit-closing position when the car is traveling in a speed zone from, for example, fifteen miles per hour to zero speed. In the speed zone between fifteen miles per hour and, for example, thirtyfive miles per hour, all of the contact members |94, |95 and |96 are in circuit-opening position.r

In the speed Zone between, for example, thirtylive and sixty miles per hour, only the contact member |95 is in circuit-closing position. In the speed zone above sixty miles per hour, only the contact members |99 and |95 are in circuit-closing position.

The pneumatic switch device may be o-f any suitable construction and is illustrated as comprising a casing 2| containing a piston 2| 2 having a stem 2|3 carrying in insulated relation thereon a movable contact member 2|@ forconnecting in bridging relation a pair of stationary contact fingers 2 5. At one side of the piston 2| 2 is a chamber 2|6 which is connected to and supiplied with fluid under pressure from the primary control pipe 11a. At the op-positeside of the piston 2|2 is a chamber 2|1, containing a biasing spring 2|8 which is interposed between the wall of the casing 2| and the piston 2|2 and'which yieldingly urges the piston downwardly to elfect separation, of the movable contact member 2M from the stationary contact fingers 2|5. When fluid under pressure is supplied to the chamber 2|6, the tension of the spring 2|8 is overcome' and` the piston 2|2 is moved to actuat-e the contact member 2 I9 into circuit-closing engagement with the contact fingers 2| 5. The tension of the biasing spring 2|9 is relatively light so that the contact member 2 I9 engages the contact member 2 I5 in response to a relatively low pressure in the chamber 2|6, such as one pound per square inch.

Control circuits Having described the construction and the operating vcharacteristics of the speed-responsive switch device |0 and the pneumatic switch device the circuits whereby the energization and the deenergization of the magnet valve devices |25, |26 and |21 of the controlvalve device 9 are effected may now be briefly described.

f The positive terminal of the battery |2 is connected to one of the contact lingers 2| 5.of the Y pneumatic switch device by a wire 296, the oppositev or negative terminal of the battery |2 being connected to ground by a wire 201. One of the contact fingers 9| |92 and |93 of each of the pairs of contact lingers are connected together and to the remaining contact finger 2| 5 of' the pneumatic switch device the one contact finger |93 being connected to the contact nger 2|5 by a wire 298, theone contact finger |9| being connected by a branch `wire 209 to the wire 209 and the one contact finger |92 being connected to the branch wire 209 by a branch wire 2|0. yThe other :contact fingers |9|, |92 and |93 of each pair are connected, respectively, to one terminal of the high speed magnet valve device |25, one terminal of the intermediate speed magnet valve device |26 and one terminal of the low speed magnet valve device |21 by wires 22|, 222 and 223, respectively. VThe opposite terminals of the electromagnet winding of the Ymagnet valve devices |25, |26 and |21 are connected by'a common wire 229 to ground, the wire 224 being connected, directly to the terminal'of the electromagnet winding of the magnet valve device |21,

the terminal of the electromagnet winding of the magnet valve device |26 being connected by a branch wire 225 tothe wire 224, andthe termi- .iti-10,634.1- h'af'off theleetrbnagnet vvidingff'the magnet vvvvalve device |25 vbeing connected to thewire byabranch Wire 226.

The Wire 224 .may be connected directly to the vnegative terminal of the battery 'I2 instead 'of' "togrou'nd, but for convenience the connectionof thejwire224 to the negative terminal ofthe batteryx-I2 isshovvnfasl being made through ground.

g Furthermore, While 'the speed-responsive switch ,f device is shown ascontrolling the magnet valve devices |25, |26 andl|21 ofthe `control yvalve device 9 on only lone car, the one speed- 1 responsive device rWill,l in practice, rcontrol the (a) Charging-In operation, 'theequipment is y charged with fluid under pressure from the main freservoir .6, fluid'under pressure being supplied tojthechamber 31 of theself-lapping brake valve lonl other cars.

magnet valve devices of control valve devices 9 Operation e device through pipe 39 and pipe and passage 38,

vand to the chamber 68 of the control Valvev device 9 rthrmigh Apipes 39' and 38, feed Valve device`69,

'25' feedvalvepipe 1|, and Ybranch pipe 12.

, Xb) Application ofr the. brakes.-Assuming that `kthecar or train of carsy is travelinglalong the trackat a speed in excess of a certain Yuniform Y high speed, such as sixty miles per hour, so thaty :sofl

y atesanapplication'of thebrakes by Vturning the Y the equipment is conditioned, as shown in Figure 1;,with .the brakes released, the operator initiv*operating handle 41 ofthe brake'control'device ffrom release position into the application zone4 a` desired amount. The brake V,control device 8 thenY operates, 'in the mannerpreviously de-v scribed', to charge the pressure chamber `I5 and 'thus the primary control pipe 11a with iluidk under pressure, vthe ultimate pressure attained being determined by the positionof the operating If, asis as-r handle 41' in theg'ap'plication zone. sinned, the vcar vor'train is traveling in excessof sixty miles per hour, theV speed-responsiveswitch 1 device I0 is actuated to the positionV shownin i Figure rl, Whereincontactmember |94 engages jcontactngers I'9| and contact member |95 engagesr the Contact fingers |92, while Vcontact member |96 is raised out of engagement with the contact'ngers |93. Upon the'supply of uid under `pressure'to the primary, control pipe 11a, the` pressure ofthe -iiuid suppliedtherefrom to the chamber 2|6 of the pneumatic switch device |I,

yeffects the actuation of Vthe movable contact member 2| 4 intoY engagement with the contact A'circuit for energizing the electromagnet windings |22 and |42 of the magnet valve devices |25 and |26isaccordingly completed'thev circuit ex Y tendingfrom Ythe positiveterminal of the battery i I Zthroughwire 206;cont`act'ngers 2 I5 and contact member 2I4 of thev pneumatic switchdevice' IIQWires 208 and 209 to thepoint 228, Where the circuit'divides into tvvobranches, the oneb'ranch 65 sponsive switch device I0, wirej22l, electromagextending through vthe wire 209,'contact1ngers I9I and contact member I94'of the speed-reynetvvinding v|22 `of the magnet Vvalve device` |25,

wires 22s and 224', and thence thrpugh the ground. j connection at 229 5 to the negative terminal lof the.(winery, I2. The other brancher the 'circuit extendsirom the point 220 throughthe wire 2 I 0,Y

contact-'lingers |92 vand contact vmember 95 of the'speed-responsive switch device |0, Wire 222,V f

electromagnet rWinding |42 fof, .the intermediate speed .magnetvalve device' 26,1wires 225 and.22.4,";

andjthence to the negative terminal of the bat- The high speed magnet valve device |25 is accordingly actuated to seat the release valve |20 and unseat the supply valve II9, while the intermediate speed magnet valve devicev |26 is actuated to seat the release valve |40 and unseat the ysupply valve |39. Fluid under pressure is thus supplied from the primary control pipe 11a simultaneously to the chamber IIvbetween the diaphragms 95 and 96 and to the connected timing chamber 65, as well as tothe chamber I6 between "the diaphragms'96 and 91 and the timing chamber-66 under the control of the magnetvalve devices|25and |26, respectively. Fluid under pressure issupplied tothe chamber I|5 and the con- Vthrough chamber |44, and passages |45 and |08.

Since thecontact member |96 is disengaged from the contact ngers |93 of the speed-responsive switch device I0, the circuit for energizing the electromagnet Winding |62 of( the low speed magnet valve device |21 is interrupted and consequently the magnet valve device |21 is so conditioned that the valve |59 thereof is in its upper seated position, as shown in Fig. 1, wherein it establishes communication for the supply of uid under pressure Yfrom the primary control pipe 11a to the chamber II1 between the diaphragms 91 and 98 and the timing chamber ,61 connected thereto, the fluid iiowing from the primary conf trol pipe 11a through the branch pipe and passage H2, passage|| I, branch passage I 6I, chamber |61 of the magnet valve device |21, past the valve |59, through chamber |64 and passages |65 and 'I'he chamber I I8 at the right of the diaphragm 98 being connected to the passage III, is constantlyfcharged with fluid under pressure from the primary control pipe 11a..

, YIt Will thus be seen that all of the chambers I I5, I6, I1 and I I8 rare charged with fluid under pressure from the primary control pipe 11a and,

'-consequently, that the fluid pressure forces acting on opposite sides to the diaphragms 96, 91 and 90 are balanced. With the release slide valve 82 in the release position shown in Fig. 1, the

Vchamber` |04 at the left-hand side of the diaphragm 95 is at atmospheric pressure, chamber |04 being connected to slide valve chamber 14 through-the portV or passage |03 inthe guiding piston |02. As a. result of the unbalance of the fluid pressure forces in the chambers |04 and II5'onrthe lefty and right-hand sides of the diaphragm 95, respectively, the stack ofr diaphragms and the valve operating stem 89 are urged in the left-hand direction.' In moving in the left-hand direction, the operating stem 09 iirst shifts the ,release valve 82 to ycover the exhaust port or passage 19 and then engages the projecting stem 88 of the supply valve .8| and unseats the valve 8| against theforce of the return` spring |36. Fluid under pressure is accordingly supplied fromv the feedvalve pipe 1I lto the secondary control pipev 11 throughy branch pipe 12, chamber 0,8, pastthe unseated` valve 8|, through the passage Sift-slide valve chamber 14, port 15 and branch pipe 15. Since the pressure in the secondary control pipe 11 determines the pressure in thebrake cylinder 1, either directly, as shown, or indirectly through relay equipment in the manner shown and described in my copending application Serial No. '141,063 above referred to, thev brake cylinder pressure is thus simultaneously built up according to the build-up of pressure in the secondary control pipe 11'to effect application of the brakes.

The pressure in the chamberV |95; at the lefthand side of the diaphragm 95 builds up simultaneously in accordance with the build-up pressure in the slide Valve chamber 14 and consequently exerts a force on the diaphragm 95 in opposition to the force of the fluid pressure in the chamber I5 acting on the right-hand face of the diaphragm y95. As the pressure of the fluid, in pounds per square inch, in the chamber lll@ and accordingly in the secondary control pipe 11, substantially equals the pressure, in pounds per square inch, of the fluid in the chamber l5, return spring 86 acting on the supply valve 8| becomes effective to shift the operating stem E9 and the stack of diaphragms to the right-hand direction an amount suicient to permit seating of the valve 8|. The supply of fluid under pressure from the feed valve pipe 1| into the secondary control pipe 11 is thus immediately cut-off and further movement of the operating stem 189 and stack of diaphragms in the right-hand direction is stopped so that the release valve 82 remains in lap position covering the exhaust port or passage 19 The brakes are thus applied to a degree as determined by the pressure of the iiuid supplied to and maintained in the brake cylinder 1.

If it is desired to increase the brake cylinder pressure and accordingly the degree of the application of the brakes, the operating handle 41 of the brake control device 8 may again be operated to a further extent into the application Zone, whereupon the pressure of the fluid in the primary control pipe 11a and in the chambers H5, ||6, l l1 and H8 is correspondinglyA increased. Due to the increase of pressure in the iiuid` in the chamber 5 acting on the right-,hand face of the diaphragm 95, the stack of diaphragms and the operating stem 89 are again urged in the lefthand direction to unseat the supply valve 8|. Fluid under pressure is thus again supplied from the feed valve pipe 1| into the secondary control pipe 11 to effect a corresponding increase in the pressure in the brake cylinder 1. When the pressure of the fluid in the secondary control pipe 'l1 and consequently in the chamber |94 at the left-Y hand side of the diaphragm' 95 becomes substantially equal to the increased pressure of the fluid in chamber I5 at the right-hand side of the diaphragm 95, the return spring 85 again becomes effective to shift the valve 8| into its seated position to close olf the further supply of fluid under pressure to the secondary control pipe 11, the operating stem 89 being shifted in the right-hand direction only sufcientlyrto permit seating of the Valve 8|, without shifting the release valve 82 sufficiently to uncover the exhaust port 19.

A full application of the brakes to a maximum degree is effected by rotating the operating handle 41 to its fullest extent into the application zone so that the primary control pipe 11a is charged to the full main reservoir pressure. The stack offdiaphragms is then shifted to the lefthand direction to--cause unseating of the supply valve 8| and-k the further supply of Yfluid under pressure fromV the feed valve pipe 1| to the secondary control pipe 11. Since the main reservoir pressure is customarily a certain knumber of pounds per Vsquare inch higher than the pressure as regulated by the feed valve device 69, the ultimate pressure attained in the secondary control pipe 11 and thus in the chamber |94 at the left-hand side of the diaphragm 95 may not be built up suiciently so that the return spring 86 can shift the supply valve 8| back to seated position. The supply valve 8| thus remains unseated for a full application of the brakes until such time as the pressure of the fluid in any of the chambers H5, IIB and ||1 Varies to cause shifting of the diaphragms back in the right-hand direction, in the manner to appear presently.

As the speed of the train reduces under the application of the brakes effected in the manner just described, the force urging the switch element |18 of the speed-responsive switch device I0 upwardly gradually decreases until the speed Vof the train reduces below the certain uniform high speed, previously mentioned, such as sixty miles per hour. The contact member |94 then disengages the contact fingers |9| and thereby interrupts the circuit for energizing the electromagnet winding |22 of -thehigh speed magnet valve device |25. The magnet valve device |25 is accordingly actuated to the position shown in Fig. 1, wherein the supply valve ||9 is seated and the release valve |29 is unseated. Fluid under pressure is accordingly vented from the chamber ||5 and the connected timing chamber to atmosphere through theV passage |01, branch passage |35, chamber |34 of the magnetvalve device |25, past the unseated release Valve |20, chamber |3| passageV |32 and choke |33. Although not apparent from Fig. 1, it should be understood that the volume of the timing chamber 65 may be many times greater than the volume ofthe chamber l |5 and thus the pressure of the fluid in the chamber |5 is only gradually reduced through the choke |33.

The reduction of the pressure of the fluid in the chamber |5 creates a differential force on the diaphragm 96 urging it in the left-hand direction, the degree of the force increasing as the pressure in the chamber ||5 reduces relative to the pressure in the chamber I6 which is maintained. However, since the diaphragm 95 has a larger pressure area than diaphragm 96, the differential force of the pressures in chambers |04 and ||5 urging the diaphragm 95 in the right-hand direction caused by initial reduction of the pressure of the uid in chamber ||5 results in a greater differential force urging the diaphragms in the right-hand direction as compared to the differential force urging the diaphragms in the left-hand direction. Thus the stack of diaphragms and the operating stem 89 are shifted in the right-hand direction to cause the release valve 82 to uncoverA the exhaust port 19.

The rate of reduction in the pressure of fluid in chamber H5, as determined by the choke |33, is less than the rate of reduction in the pressure of the secondary control pipe 11 and the chamber |94 through exhaust port 19 and Vthus when the pressure of the fluid in the secondary control pipe 11 and in the chamber |04 of the control valve device 9 is so reduced that 'the differential force urging the diaphragm 95 in the right-hand direction becomes less than the differential force urging the diaphragm 96 inthe left-hand direc-` tion, the stack of diaphragms and the operating stem 89' will be shifted in the left-hand direction so that the slidefvalve 82 is. moved to cover.,.the

exhaust port 19and cut-olf the further release Vofiiuiduhder pressure from the secondary y'con. trol pipe 11, and thechamber |04. l

However, as the reductionof the pressure of theiluid in the chamber 4I I5 further-continues,

theY differential force urging the diaphragm `'95 inthe right-handr direction again becomes greater than the cliiferential force ofthe fluid pressure in V,chambers and. I I6 urging thefdiaphragm- 96 .fin-the left-hand direction so that the diaphragms f and thev stem 89 areagain shifted' in, the 'right- .f hand direction to causeslide valve 82 touncover .exhaust-port 19 and thusL effectfurther. release y of fluidunder pressure'fromtthesecondary conftrol-,pipe 11 and chamber|04.

Y. 95- tcll the `right-hand .direction againv y becomes less: than the differential force of the fluid pressure inchambersv II,5 and; |I6 urgingthe dia-` phragm 96 in the'left-hand direction, so that the stackof diaphragms .and :stemfi89- are: again f'shifted tothe left-hand direction to causefthe slide'valve'82 to covertheexhaust port19. ,Y It :will be thus seen that the secondary control pipe pressure and correspondingly the brake cylinderpressure is reduced at a: rate1 governed by `the rate of reduction of the Apre/s sureof. the rfluid in chamber I.I5 and theconnected timingcham- *Ibex-65.*" i i '1, The capacity ofthe timingichamber 65 relative I I I5 will be completelyv vented toatrnospherewhen j Y to the chamber III5, and theI size of the-choke m35-are suitably designed so -vthat the chamber thespeed'oftravelof the lcar or'trainais reduced r.under thebrakey application to aespeedflslightiy' 1rabove-,the certain'uniformintermediate speed: of

"thirty-five miles per hour. fWhen-thechambel" v|1|5 and the connected timing chamberESware completely ventedto'atmosphere-the force urging kthe stack of Vdiaphragmsfin, the right-hand direction .isf` determined yby the secondary control fpi'pevpressure acting in` chamber |04-on the: effec# ,tive areaof the diaphragm 95` whereas theforce urging the# stack of diaphragmsgin;theleft-hand ,'larea ofthe;diaphragm.96.`r n

" The pressure to which;v the secondaryl control f direction is determinedfby theY pressuref of the fluid in the chamber I |6 acting over the effective rpipe'fpressure andthe ypressure in the 'chamber '|04 vis reduced, With'the diaphragm: chamber I I5 completely-vented,andathe chambersjl I6,` II 1 and llastill'maintained charged at the pressureof ,the primary control pipe 11 a,-` compares to the pressurein the 'primary control pipe in the same ratio asv the effective area of thel diaphragm v96` compares to the effective area,vv of the diaphragm 95. vThe reason for this should. be obvious since v 'it `requires a lesser pressure in the chamber`|04 actingjover the larger area of the diaphragm 95 to" balance a higher pressure acting in chamber I I6 on the smaller area;y of the diaphragm` 96.7,.. rr Assumingthatthe, primarybcontrolpipe, is

` r c,hargedto Aa pressure ofvcnehundredv poundsper square inch and .that the effective area of .the i diaphragms. 96, 91 and Sil-.may be expressed f'asthree; two, one and one-half, and one unitsY of area,` respectively, the lsecondary control-pipe pressure and thus the brake `cylinderpressure will beara ratio to thev one hundred pounds primary ,controhpipe pressure of two to thre,e,tha,t is, it

will be substantiallysixty-six pounds per square inch'.

When the speed of a. car or train reduces below the intermediate uniform speed of thirty-ve miles per hour, the contact member |95 of the speed-responsive'switch device I0 disengages the contact lingers I 92e thereby interrupting the circuit for energizing theelectromagnet Winding |42 of theintermediate speed 'valve device |26. The supply -valve |39- and the release valveMD of the magnet. valve devicek |26 are accordingly actuated to seated and unseatedpositions, respectively, to cut-off the supply of primary control pipe pressure tothe. chamber-| I6 and the timing chamber 66 atthe seated valve |39, While at the same time opening the exhaust lcommunication at' the unseated .valve I4Il, through .which fluid under presi sure is vented from the chamber kI IISy and connected-ftiming` chamber |66- to atmosphere. kFluid under pressurevis vented from chamber |I6 and connected V`timing chamber v 66- to atmosphere through the passage,|08, -branchipassage..|45,

vchamber |44e past the unseated release .valve.|40,

chamber |5I, passage |52, and choke. |53.y

When the pressure of the fluid in the chamber I I6 reduces, the differential force of the pressure acting on the diaphragm 91 and urging the stack of diaphragms inthe;lefthand direction. The stack of diaphragmsand the release slidevalve 82 .are shifted accordingly in` the right-hand direction to uncoverthe exhaust port 19 andr to a further extent to vent fluid under pressurev from r9.5. and 96 in theright-hand.direction or the diflerentialforce von diaphragm 91 in the lefthand.y direction ,predominatem ThusY secondary control pipe pressure .and .the` pressure in the chamber, |04 is reduced at a rate determined by the size ofthe timing chamber 66 and-thefsize of the, choke |53 whichare so selected and designed that the chamber IIG and the timing chamber 66 will bewcompletely vented to atmosphere by the time,A the car or-train of cars is reduced to a speed pletely ,vented to atmosphere and withV the chambers IVI'I and |I8still charged to the pressure of the primarycontrol pipe 11a, the force urging the rstack of .diaphragms to the left-hand direction,.in opposition to the force of the fluid presysure inthe chamber |04 acting on the left-hand rpointin the operation, Will thus bear the Vsame ratio to the pressure in the chamber I I1, that is, primary control pipe pressure, as the area of the diaphragm 91 bears to the area of the diaphragm sure will be fifty pounds per square inch.

As the speed of the travel .of the car or train of cars decreases to below the certain uniform low speed of fifteen miles per hour, the contact membei1 |96 engages the contact fingers |93 of the speed-responsivev switch device I0 and completes the circuit for energizing the electromagnet winding |62 of the low speed magnet valve device |21. This circuit extends from the positive terminal of battery |2, through wire 206, contact fingers 2i5 and contact member 2 |4`of the pneumatic switch device wire 208, contact iingers |93Vand contact member |96 of the speed-responsive Vswitch device |0, Wire 223, electromagnet winding |62 of.

magnet valvedevice |21, wire 224, and thence through ground to the negativeterminal of baty vented to atmosphere from the chamber i |1, be-

When thepressure of ,the 4iiuid i1 is reduced, as just described, the stack` of. dia.-

phragms is urged in the right-hand direction by Y the differentialforce of the iiuid pressurein chamber |1 acting on the righthandfaceof the diaphragm `91 andthe uid pressure ,in chamber |04 acting on the left-hand face of diaphragm 95 ink opposition to the lesser diierential forcenof the pressure in chambersV ||1 and Il! i9 raci-.ing on the diaphragm 98 and urging. it in the left-hand di.- rection. The, stack of ,diaphragms and the valve operating stem |39v are accordingly shifted in the right-hand direction so as to move thevalve 82 to uncover the exhaust port 19 andv again further reduce the pressure in the secondary .control pipe 11 and the chamber |04. As in the case of the reduction in the pressure of the fluid inthe cham- Vbers ||5 and H6, the stack of diaphragme. .is

Yin theleft-hand direction. Accordingly, the secondary control pipepressure and the pressure in the chamber |043 is reduced at a ratewhich is governed by the rate of reduction of the iiuid pressure in the chamber ||1, the brake cylinder pressure being correspondingly` reduced.

The size of the choke Y|13 and the volume of timing chamber 61 relative to the volume of chamber ||1 is so designedthat the 'pressure in chamber ||1 is reduced to atmospheric pressure,

that is the chamber-||1 is completely vented,y

when the train of cars is traveling at, for example,

only Atwo or three miles per hour just before the car or train comes to a complete stop.

With the chambers I l5, I6 and ||1 completely vented and the chamber H8 still charged atV the pressure in the primary control pipe 11d, vthe pressure ,to which the secondary controlY pipe pressure and the pressure inthe chamber |04 is reduced bears the same relation to the pressure inthe' chamber H8 and in the primary control pipe 11a as the area of the diaphragm 98 bears to the area of the Adiaphragm 95.V If it is assumed that thef area of the, diaphragm is expressed as three units of area andthe area ofthe diaphragm 98 is Vexpressed as one unit of area, then the pressure in the secondary control pipe 11 will be one-third that in the primary control ,pipe 11a. If the primary control pipe pressure be a hundred pounds per square inch, then the secondary control Vpipe pressure will be approximately thirty-three poundsper square inch at'the time the car or train is brought 5to a complete stop. The brake cylinder pressureV will thus be reduced to a pressure in' accordance with that in the secondary control pipe 11a.

It Willthus berunderstood' that when yan application ofthe brakes is initiated at the time the train is traveling in excess of a certain uniform high speed of, for example, sixty miles per hour,

a pressure in the secondary control pipe 11 and in the brake cylinder 1 is initially established which is substantially equal to the pressure in the primary control pipe 11a as determined by the degree to which the operating'handle 41 of the brake control device 8 -is moved out of release position into the'application Zone and thatthe pressure in the secondary control pipe and in 'the brake cylinder 1,is` automatically gradually reduced under the control 'of valve device 9 until 'at the vtime the' car or train is brought to a stop theVV pressure in the secondary control pipe V11 and correspondingly in brake cylinder 1 is only a fraction of the pressure in theiprimary' control pipe 11a.` Itwill be further understood that the operation of the control valve devicev 9'is such as to reduce the VpressureV in the secondary control-pipe'and in the brake cylinder, as the speed of travel of caror trainl reduces, Without any change inthe pressure in the .primary control pipe. Thus the operator may x the pressure in the primary control pipe 11a and the control valve device 9 automatically .adjusts the pressure in Y .the secondary control pipe 11 and the brake cylinder 1 to a Vvalue which'is proportional to the pressure maintained in the primary control pipe and which is kgradually reduced as the speed of travel of the car or train reduces under the application of the brakes.

If the pressurein the primary control pipe is established and maintained at a certain'pressure,

the control valve device `9 veffects gradual reduction in the secondary control pipe pressure and in brake cylinder pressure along auniform curve If thesprimary control pipe pressure is xed at a pressure higher or lower than the certain pressure, then `the control valve device 9 gradually reduces the secondary control pipe pressure and the brake cylinder pressure along uniform curves higher or lower, respectively,than that for thel during the application of the brakes, the pressurev vin the chambers H5, H6, ||1 and H8 changes accordingly so that the reduction in the secondary control pipe pressureand in the brake miles perv hour, and abovethe intermediate uniformlspeed of thirty-tive miles per-hour, the magnet' winding I|22 `of thelhigh lspeed magnet valve device-|25` is not energized,v duetov theffact the contact member '|941of the speed-responsive switch-device I0 is not raised: sufliciently to engage thecontact ngers |9|. rThereforey the chamber 51 between the diaphragms- 95 and 96 and-its connected timingrchamber `65 'remains ventedto atmosphere pastthefunseated'valve |20.

Consequently, instead of an initialsecondary control pipefpressure being obtained which is subr stantially equal to the primary .control pipe pressure, the 'initial secondaryrcontrolpipepressure will bearva ratio to theprimarypontrol pipe pressure established` which' equal to the ratio of the`areaof the .diaphragm 96 to the varea of the diaphragmy 95. Ifthe same illustrative diaf y phragmrareas areusedf as inthe prevlouslydelscribed operation, thatis, if the diaphragm 95 is 7of three units of area'and diaphragm 96 is ofl two units-of area, and if'the' primary controlpipe f is'chargedtc .apressure of one hundred pounds iper-square inch, then theinitial vpressure obtainedl in .the secondary control. pipegand. correspondingly inthe brake 'cylinder-1, will be two-thirds of kthe -primary controlfpipepressure, thatiis twothirds of: one' hundred pounds! per square inch, or substantiallysiXty-six pounds perr square inch.

As the speed of travel of they car ortrain subse- Vquently reduces, the operation of the' controlV dervicef9 thereafter is Aidentical'with that'p'reviously k'described and itis, therefore, not repeated here.

In va similar manner, if anfapplication of ther brakes" is initiated when thev caror .trainlis travel- Wing at Vaf: speed below 4thelintermediate yuniform speedofthirtyflve miles per hour,` but above the Vcertain uniform lowl speed of fteen miles per hour, thenY both the high speed magnet valve dekvice'xl 25 and the intermediate speed'magnetvalve .device |26 are not energized upon the operation of thepneumatic switch device ||`to cause actuation' ofz the contact Amember 2 |4 to circuit-'closing position. Consequently, both'of the chambers ||5' and f| I6 remain ventedto atmosphere, vwhile K only-the chambers and'l |8are charged with -uid under pressure fromtheiprimary control pipe 1111.1 Thus, the initial pressure obtained, 'in

y,such case, 4in the secondarycontrolpipe 11, and in the brakecylinder bearsta'ratl'o to the priv mary controlpipe pressurewhich is equal to the rratiocf the area of lthediaphragm yS'Itci'the area of the diaphragm 95. If it is assumed, as in preivicusinstances, thatthe ratio of the area of the diaphragm 91 .to the area of the diaphragm 95 `isequaltorthe ratio of onefand one-half to three,

, thenthe 'initial pressure obtained in the secondary control pipe and the brake cylinderlzl. is

fone-half of one 'hundred pounds or fty pounds :per square inch. Y

Thereafter, as the speed of travel of the car or train reduces, the control valve-device 9 operates, y Vas previously described, to effect reductionv in the tof-a complete stop, the nal secondary control pipe .and brake cylinder pressure being `difierent depending upon thepressure in the primary controlpipe 'lla' but always bearingal ratiofto the primary control'pipe'pressure which is equal to the ratio vof the area of the smallest'diaphragm 98 to the largest diaphragm 95.

l In a similar manner, if an application of the brakes is initiatedat a time that the car' or train is traveling at speed below the certain uniform low speed of fteen mil-es per hour, the electro- .magnet'winding |22 of the low speedmagnetvalve vdevice |21 is immediately energized upon the engagement `of the contact member 2 I4 with the Contact fingers 2|5 of the pneumatic switch device since the co-ntact member |96 of the Vgovernor switch device l0 is already in engagement with the contact ngers |93. Accordingly, the magnet valve devices |25, |26 and |21 are conditioned to .vent to atmosphere the chambers 5, ||6. and respectively. Thus only the chamber 8 is charged with iluid under pressure from the primary control pipe 'Vla and the initial pressure attained in the secondary control pipe Tlfaccordingly bears'a ratio to the primary control pipe pressure which is equal to the ratio of the area of thefdiaphragm 98 to the area of the diaphragm 95. If, as assumed previously, the area of 'the diaphragm 98 and the area. of the diaphragm 95 have a ratio of one to three, and if for examplethe primary control pipe pressure Ais onelhundred'pounds per square inch, then the initial secondary control pipe pressure attained is one-third of one hundred pounds per sqluare inch or substantially thirty-three pounds perfsquare inch. The pressure attained in the Vlorakec'ylinder accordingly corresponds to that jin the' secondary control pipe 17.

If the primary `control pipe f pressure is not i changed during the application of the brakes,

'the' initial secondary control pipe pressure and brake cylinder .pressure remains unchanged thereafter untilf such time as the pressure in the primary control pipe lla is reduced by operation of the brake control device 8 or until the brakes i are completely released by reduction of the primary control pipe pressure tc atmospheric pressure, in the manner to be hereinafter' described mary control pipe 'lla and in substantially the same ratio to the pressure in the primary control pipeas the ratio of the area of the smallest diaphragm 98 to the area of the largest dia- 1 h1fagrn95-`y If there is leakage from the brake cylinder and thesecondary control pipe, the reduction of the pressure in the chamber |04 incident thereto results in shifting of the diaphragm in the left-hand direction by the primary control pipe pressure maintainedin chamber ||3 and acting on the right-hand face of diaphragm 93, If there is suicient brake cylinder pressure leakage, the supply valve 8| will be unseated by the shifting of the diaphragmin the left-hand direction and liuid under pressure will be accordingly supplied 1 from the feed valve pipe 1| tc the secondary control pipe 'l1 and accordingly to the brake cylinder until'the pressure acting in chamber |34 is again sufficient to cause shifting of the diaphragm in the right-hand direc ion to permit the supply v valve 8| to reseat. Thus, control valve device 9 maintains brake cylinder pressure against leakage at all times. This is of particular advantage where the train is stopped on a grade and creepage of the train wouldY result if the degree of quate braking force to hold the train at a standstill on a grade.

summarizing in part, it will be seen that the degree of the initial secondari/'control pipe pressure and the pressure in the brake cylinder will be greater or less depending upon the speed of travel of the car or train at the time the application of the brakes is initiated being greater or less, respectively, and that the secondary control pipe and brake cylinder pressure is gradually re- Vduced from the initiall pressure attained to a certain uniform low pressure which is proportional to the pressure established or maintained in the primary control pipe lla.

' (c) Release of the brakes-'Assuming that an application of the brakes has been effected, in

the manner just described, and that the car has been brought to a complete stop, the brakes mayV be released completely prior to again-'putting the carin motion by shifting the operating handle l1 of the brake control device 8 into releaseposition so as to completely vent fluid under pressure from the primary control pipe lla. chamber II at the right of the diaphragm 98 and the chamber ZI@ of the pneumatic switch device II are constantly connectedk to the primary control pipe 'I'l'a, reduction in the pressureY in the primary control pipe to atmospheric pressure is accompanied by reduction of the pressure in the chamber |I8 and ZIB to atmospheric pressure.

As the pressure of the fluid in the chamber I I8 reduces, the force of the pressure in the secondary control pipe and in the chamber Id acting on the left-hand face of the diaphragm 95 becomes greater than the vforce of the pressure of the fluid in chamber H8 acting on the righthand face of the diaphragm 98, and consequently the stack of diaphragms and the operating stern 89 are shifted in the right-hand direction to move the valve 82 to uncover the exhaust port 19. Fluid under pressure is accordingly vented from the secondary control pipe 'Il and the chamber It@ and a corresponding reduction in brake cylinder pressure produced. Since the chamber I I8 is relatively small compared toi the chamber |84 and since the chamber YI I8 is vented at a relativelyY rapid rate, the pressure in the chamber |04 continues to predominate and maintain the stack of diaphragms and the operating stem 89 biased in the right-hand direction to such an extent that the slide valve 82 continues to uncover the exhaust port 79. Fluid under pressure is thus completely vented from the secondary control pipe and accordingly the brake cylinder 'I to cause complete release of the brakes.

'tain additional Vadvantageous features. the advantageous features of the control valve Since the VI'Ifloliyi,celu/pe,orcontrol valve device as shown in- Figs. 2,3, and 4 A modified type of control valve device 9a, shown rin Figs. 2, 3 and 4, may be substituted for the control valve device 9 of Fig.4 1. The entire control valve device 9a is not shown in Fig. 2,

similar manner all the functions of the control valve device Il Vand is also adapted to provide cer- One of device 9a is that itY enables the rapid corresponding adjustment ofthe Ysecondary control pipe I ture of the Vcontrol Valve device 9a is that it functions upon application of the brakes at speeds below a certain uniform low speed to `cause the pressure inthe secondary control pipe TI, and accordequal to or in one to one ratio. with the pressure in the primary control pipe 11d until' such time as the brake shoes come into contact with the car Wheels instead of in the ratio of the area of the smallest diaphragm of the stack to the area of the largest as in the control valve device 9.

It will be appreciated that in the event of an application of the brakes being effected in the brake systemshown in Fig. 1 'at a time that the car or train is traveling at a speed less than a certain uniform low speed, such as fifteen miles per hour, the control valve device-.9 is so conv ingly inthe brake cylinder l, Ato be substantially structed and operates in vsuch manner as toV require the build-up of a pressurein the .primaryY ingly in the brake cylinder I to move the brake shoes into contact with the carwheels. is Well known, it requires a build-up of the pressure in Y the brake cylinder to substantially five pounds per square inch in order to lmove the brake shoes into contact with the car Wheels and thus if, as has been previously'assumed, the ratio of the area of the largest diaphragm of the control valve device 9 to the area ofthe smallest `diaphragm 98 of thercontrol valve device 9 is three to one, it follows that the control valve device 9 necessitates a build-up of pressure in the primary control pipe 'Ila to a pressure of fteen pounds per square inch in order to cause a pressure of fiveV pounds per square inch to be built up in the secondary control pipe 'I'I and accordingly in the brake cylinder 1. n

It will be apparent therefore, that it is desirable .to'cause an equal pressure in the secondary oontrol pipe 'I'I as compared with the pressure in the primary control pipe 'Ila in the case of applications of the brakes initiated at the time that the train or car Vis traveling at a relativelyv low speed, in order to insure rapid response to the initiation of an application of the brakes.

The provision of the vfeatures just described is accordingly among the objects of my invention.

Referring-to Fig. 2, the essential differences in the construction of the control valve device 9a f yover the control valve device!! comprise the pro-v vision of a 4modified form of relay valve casing ysection 6m. in place ofthecasing section 61|, the

ycasingy section 6|a havingeernbodiedftherein a.

modified form of relay valve-.mechanismv 24|., a

single4 casing section 62av instead of the plurality 295; 296, 291 and 298 mountedin .thei casing 62a.

and corresponding'to the; diaphragms 95, 96, '91.

* and98, respectively, of the control valve device 9 the diaphragms 295, 296,k 291`and 298 being en`- tirely unconnected with each otherv as compared 5 'tothe diaphragms 95, 96, 91 andz98 which are.y

connectedv together. VFurther differences in the construction of the control valve Vdevice 9a;over the control valve device 9 comprise therprovislon of :an end casing section 10 {adapted to carry 'an additional movable abutment ordiaphragml `299 and` associated lever mechanism which will be described' presently vand which functions to cause f build-up 'ofV pressure in the secondary control pipe 11 *equallywiththebuild-up of pressure-in` the primary control pipe 11a until the brake shoes contact the car wheels; 1 l 'I'hecontrol valve device Saalso includes aplu.-VV ralityof check valves 495, 496 and `491Ii`n the g casingsectionf 62a for permittingor enabling the 3dr-'amd adjustment of the `fluid pressure in the chambers between the diaphragms upon a'reduc'- tion in the pressurerin'the primary control pipe 111 under .the control of the. self-lapping vbrake 351 theclamping face thereof in which issupported.

valve device 8. Y Referring, in further detail to Fig. 2,l therelay valve casing section l6 la has a circular bore 243 `in and'guided a follower disc 244 for the largest of thediaphragms 295.

246 "and 241"whch open into the bore 243 are alsoformed in the casing6 la, the bores beingdiS- posed side by side in fa row in parallel .relation (Fig. 4). .'IhelooresI 245and246 are open .to each other at the outer ends :thereof'through a slot 248 I in the' casing and the bores 246and1241 are simi- 45`r 1 a slot 249 ,inthe casing.' yFormedinthecasinfg larly connectedv at the outer ends thereof through 6|a is a ohamber'25ls`which'is constantlyfconnected to fe'ed'valve pipe 1| through the branch pipezJZ and which is ,connected to thesinnerend cow ofthe bore 241 througha borei or passage .2252. Contained inthe chamber'25ltis' al supply valve 253I having al uted stem 254 which slides ini the borez252 and extends into `the bore 241, the 'valve y,253".being yieldingly urged into seated relation f on Van associated valve seat to close the connection between. the. chamber .25| and'the b0rez241 through the passage' 252i by'la -coilV springf'255 which is interposed between the valve 253 fand the screw plug 256 closing thevchamber 25|. i

` .Contained in and slidably operable inthe bore 245 is ar piston 251 havingxa valve member 258,

.which is formed on or ,secured thereto'and which 'willbehereinafter designated theV release valve.

1 The releaseivalve 258 has a fluted stem 259 which yis .guided in a bore 26|,y the bore 26| being 4confstantly open to atmosphere through an exhaust port262.

.f A chamber 26,3 formed in the bore 2'45 between '.the'inner end of the bore andthe piston251, Vvwhich chamber 263 is constantly connected to the secondary control pipe 11 through a branch pip'e and passage `16, is4 connected to atmosphere A plurality of bores: 245;`

formed at "one end as a piston 269 which slidably operatesrin the bore 246 which is betweenr the bores 245'and 2,41.

The Vpin 261 is inserted in and secured in a transverse bore or hole 21| extending through two spaced parallel portions 212 ofthe plunger 268, 'withgthe floating lever 265 carried on the pin A261in the space between the parallel portions 212 ofthe plunger. The lever 265 is sopositioned as to .have one armthereof ,extend through the slot 248 into the bore 245 and the other ,'arm"` extend throughtheslot 249 'into the bore 241.'. `Slidable in a reduced inner end por-V tion of the bore 241 is a fiuted spacer 215,'one end of whichl engages' theend'of the fluted' stem 254 of the supply valve 253 and 'the other end of 4which is adapted to 'be engaged bythe rounded endv vof the arrnof leverV 265 inthe bore 241.

Thesouter portion of thebore 241 is threaded toreceivea stop screw 216 and' a locking screw 211., va 'lockJdisc' 218, Fig. '5, being Ainterposed betweenA the 'stop' screivand'v the locking screw which has'al tongue 219' extending into the slot 219 to prevent rotation'of thelock disc 218 upon tighteningof 'the Alocking screw 211.'

The oppo'site'arm` of the"'floating"lever4 265 is rounded at the enda'nd forked to 'straddle' Va stem 28 secured vto the vpiston 251' carrying the release valve 258,the7stem 28| having two spaced collars yor flanges- 282 and 283', between which the round! plunger' 268"'on: the" interior of kthe Apiston 269 formed'at the lend of lthe plunger 268,'yie`ldingly urgesl'the plunger268 in the right-'hand direction, the outer end 'of 'the' plunger 268 having a rounded' head 286 thereon which'is adapted to contactthe`1face of 'the follower membe'r244 associated'withI the largest diaphragm'` 295.

, A bezel ring 281 suitably secured 'to the casing at theV outer end vof the bore245 serves as a stop to 'limitth movement of the piston 251 outwardly of the bore 245.

When'force' 'i`s appliedto the diaphragm; follower" 244 by means of fluid pressure acting4 on the diaphragm's 295, 296, 291 and 298 inthe manner similar to that previously described for' the diaphragms'l of 'the control valve vdevice 9, the

plunger 26s isY shifted 'irl the kleft-mma direction' againstthe forc of the spring 285.Y The biasing spring 255 holding the supply valv'e 253V seated, is sufciently'strong ,t'o hold the 'end'of the arm of theleve'r '265b'etweenthe uted spacer 215 and the stop s'crew'216 against vinitial movement. Thusg'the' lever"f2 6 5"' fulcrum's at the lower vend thereof, andthe 'Opposite'or forked end of the levefv'zss' is moved-in a1 heft-hand 'direction to shift'the pi'stofi`251 andtherelease valve 258 into seated relationfon itsy associated valve seat to close 'the connection of the' vchar'nber263 with the 'atmosphere' `through the" port 262.

Further' movement o f the plunger 268l in the lefthandidirec'tlon results in the pivoting of the lever 265 at the upper forked end'thereof', which is prevented frommoving further in thelefthand direction after the release valve 258 seats, to cause the lower end of the lever 265 to be shifted in the left-hand direction and thus, through the fluted spacer 215 and the valve stem 254 to effect unseating of the supply valve 253. i Upon the relief of the force applied to the followerv 244, spring 285 returns the plunger V268 Y in the right-hand direction. The biasing spring 255 acting on the supply valve 253 then becomes elfective to reseat the supply valve 253 while at the same time maintaining the release valve 258 seated by pivotal action of the lever 265v on the pin 261. As the plunger 268 continues to move in the left-hand direction after the supply valve 253 is seated, the lowerend of lever 265 engages the stop screw 216 and the lever is thus pivoted at the lower end thereof in a clockwise direction to shift the piston 251, and the 'release valve 258 in the right-hand direction so that the release valve 258 is unseated from its associatedvalve seat and the connection of the chamber 263 to atmosphere through the port 262 vagainfvestabv lished.

The casing section 62a whichis secured between the casing section 61a and the end casing section 10 in any suitable manner as by stud bolts 338 provided at opposite ends with nuts 340 has therein a stepped bore 288, one end :of which opens at'the clamping face of the casing section 62a engaging the casing section 61a and the opposite end of which is open to a chamber 398 which is in turn open at the oppositeface of the casing section 62a.

A plurality of clamping rings 291, 292 and 293 of successively smaller diameters are provided for fitting closely into the portions of the vstepped bore 288 of corresponding diameter for clamping the diaphragms 296, 291 and 298 respectively. The largest diaphragm 295 is suitably clamped between the clamping'faces of the casing sections 61a and 62a. Y `f i Each of the diaphragme 295, 296,' 291 and 298 is provided with a projection 294 at the center thereof for closely fitting into a cooperating re# cess at the center of follower plates or discs `301, 302, 303 and 304 respectively. K

'Ihe follower disc 301 is associated with'the right-hand face ofthe largest diaphragm 295 and is provided with a peripheral skirt or flange 306 having ports 301 therein, the skirt 306 being adapted to engage the clamping ring 29| to limit the movement of the diaphragm-295 in the righthand direction.

The follower disc 302 is associated with the left-hand face of the diaphragm, 296 and has a central projection 308 and a peripheral skirt or flange 309 having one or more ports 310 therein, the end of the projection 308 and the end ofthe flange 309 being adapted to engage the follower plate or disc 301 on the right-hand face of the diaphragm 295. f In a similar manner, thefollower disc 303 is associated with the left-hand face of the dia, phragm 291 and is provided lwith a central projection 311 and a peripheral'skirt or flange 312 having one or more ports 313 therein, the Vouter end of the projection -31 I andV -the edge Vof the flange 312 being adapted to engage the righthand face of the diaphragm 296. In a similar manner also the `follower disc'-304 is associated with the left-hand face of the diaphragm 298 and has a central projection 314 and a peripheral skirt or ange 315 provided with one or more ports 316, Vtheend of the projection 314 and the edge of the flange 315 being adapted to contact theright-hand face of the diaphragm 291.

Associated with the righthand face of the smallest diaphragm 298 is a follower disc 318V and 61 in casing 64, not shown, through passages Y 101, 108 and 199, respectively, which passages correspond to the passages 101, 108 and 109 of the control Valve device 9 shown in Fig. 1. Magnet valve devices, not shown, corresponding to the magnet valve devices 125, 126 and 121 of Fig. 1, act to controlthe supply of fluid under pressure from the primary control pipe 11a intosaid passages -101, 108 and 109, respectively and the release of fluid under pressure from said passages in the same manner as in Fig, 1.

Formed in the casing section 62a are a pluralityiof chambers 325, 326 and 321, which chambers are open to each other and which are connected to the'chamber 398 in the casing section 62a` through a passage 331. open to the chamber 325 through a branch passage 335, the passage 108 is open to the chamber 326 through a' branch passage 336 and the passage 199 is open to the chamber 321 through a branch passage 331.

The check valves 495, 496 and 491, previously mentioned, are contained in and suitably guided in the chambers 325, 326 and 321, respectively, and are each yieldingly biased by a coil spring 494 into seated relation on an annularV rib seat 493 to prevent back flow of iiuid'under Vpressure from thechamber 325 to the passage 335, from thechamber 326 to the passage 336, and from the chamber 321:' to the passage 331, respectivel while at the same time being adapted to permit flow offluidunder pressure therepast in the opposite direction.

Y The chamber 398 is constantly connected to the primary control pipe 11athrough the passage 1 11, corresponding to the passage 111 of the control Avalve device 9 shown in Fig. 1.

The outer opening of the chamber 398 in the casing section 62a, is closed bythe end casing section 10 which is secured' to the casing section 62a, by the stud bolts 338. On the inner face of the casing section 10 is a recess or chamber 339 which is closed at the inner end thereof by the diaphragm 299. The diaphragm 299 is secured at the periphery thereof by means of a clamping ring 341 which is secured to the inner rface of the casing section 10 by a plurality of screws or bolts 342. The chamber 339 is constantly open to atmosphere through a port 344 in a stop The passage 191 is screw 345 turned into a threaded opening 346 in the wall of the casing 10, the stop screw 345 being locked in a desired position by a lock nut 341.`

The diaphragm 299 is clamped centrally thereof and which has a suitable nut 352 on the Yend thereof for applying clamping pressure to the follower discs. A pair of spaced levers` 353 are provided, as shown in Fig. 3, which are each r pivotally mounted intermediatethe ends thereof aVT and the wall of the casing section serves to v Y '361'in`the casing section'10.

Vries a collar or flange 368, which is secured therelon alpin 354 carried on projecting lugs 355 formed on the clamping ring 34|. "One end of each of thelevers is pivotally connected by a pin `351to projecting lugs 356 formed on `orsecured to the follower disc 348 associatedwith the diaphragm n 299.',-A lever'359 disposedy between the spaced leversy 353, is pivotally connected at' one end to l, the .l opposite end of both the levers 353 as by a ypin 36|. l l f i The' opposite end'` of thevlever 359 is providedv with ar recess 363 in whichone end'of astem 364 isfreceived, the stem 364 extendinglthrough ia. suitable opening 365 in the clamping ring 34| and having a rounded or spherical head 366 at theopposite end thereof guided in a suitable bore The stem 364 carto as by apress flt, and a biasing spring v369 interposed between oney face lof the flange 368 n normally yieldinglyurge the stem 364 in the lefthand direction until theV flange 368'engag'es the n," clamping ring 34|. 725i'.

, Afpair ofv projecting lugs 31|' secured to or Formed on or securedto the lever 359 sub- 1 stantially centrally between the ends of thelever is a projecting lug 313 which is adapted to engage 405 in a clockwise direction, as'viewed in Fig. 2, aboutk the pins 354 and the lower end of the lever 359` a rrecess 314 in the right-handl face ofthe follower disc3|8 associated with `the right-hand -,faceof the smallest diaphragm 298.

Whenfiiuidy under pressure is supplied to the chamber 3.98 it acts on the left-hand face of the diaphragm 299 to urge it in the right-hand, dif recticn.` The levers 353 are accordingly pivoted is accordingly shifted" in the left-hand direction l l, with the upper end of the lever 359` pivoting on diaphragm 299.

the yend of the stem 36,4; Force is accordingly applied; by the lever 359, vurging the stack of diaphragms in the left-hand direction, the force being proportional to the vforce acting on the The spring v369 is of such strength and is so 1 tensioned that the fluidpressure acting on the diaphragm 299 in the'chamber v398, is ineffective to cause the stem r364 to be shifted in theright'- hand direction until substantially five lpounds per square'inch of pressure has been built up in the secondary control pipe 11.

The effective area of the diaphragm v299 is so proportioned as to counterbalance the force of the biasing spring 285 acting through the plunger k268 to urge thestack of diaphragms in the righthand ,direction and to cause such additional n force to be imposed on thestack of diaphragms kurging them in the left-hand direction ias to ',cause'the same pressure to be built up in the 1 secondary control pipe 11 as exists in the primary '1 control pipe 11a and accordingly in the chamber 39s.

Whenthe pressureof the fluid'in the primary control pipe 11a and accordingly in the chamber 393 exceeds the value of five pounds per squareY inch', the force urging the diaphragm 299 in the right-hand direction and the stack of diaphragms in the 'left-hand Vdirectionjis sufficient to' rovercome jtlie.y tension, of .the spring 369 to permit y shifting ,of the stem 364 in the'right-hand direction and. thusto prevent the" further jincrease ||6 and I1, respectively, of the control valve device9 by means of magnet valve devices corresponding to the magnet valve devices |25, |26

, and |21 which are under the control of aspeedresponsive switch device identical with the speedresponsive switch device l0 shown and described inconn'ection with Fig'. 1, it is believed unnecessary to describe in detail the general operation ofthe rcontrolwvalve device 9a. Therefore, only so much of theoperation of the control valve device 9a. as ldiffers vfrom that explained in connectionwith controlvalve device 9 will be described.

Let it `be assumed that the car or train is travelingalong the tracks at a speed below the certain uniform low-speed of fifteen miles per hour and that the self-lapping brake control device 8'has beenoperated to charge the primary control pipe 11a and accordingly the chamber 398 1in thecontrol valvedevice 9a to a pressure corresponding to the position of the operating handle 41 of the control device 8 in the application zone. As will be remembered from the operation of the control valve device 9 previously described, the chambers`395, 396 and 391 correspondingto thechambers H5, ||6 and ||1 of the` control valve device 9 are vented to atmospherein such case, Thus, as the pressure of the fluid increases in the chamber 398 at the right-hand face ofthe small diaphragm 298, the stack ofv diaphragms 295, 296, 291 and 298 is urged in the left-hand direction by a force which is equal to the force of the pressure acting on l.the right-hand face of the small diaphragm 298 plus the force of the pressure acting on the left=handface of the'diaphragm 299 and transmitted, through the levers 353 and 359, to the follower 3|8 Von the right-hand face of the small diaphragm 298; 'I'he plunger 268 of the relayffvalve `mechanism 24| is accordingly shifted inthe left-hand direction against the force of the spring 285 to first seat the release valve 253 and then unseat the supply valve 253. Fluid under pressure is accordingly supplied from the `feed valve pipe 1| to the secondary control pipe and passage 16. Thepressures on opposite sidesv of the piston `269- of the plunger 268 are equalized through a port385 inthe piston, it being apparent'that fluid under pressure supplied into the bore 241 flows past the fluted spacer 215, through the slot 249 into bore 246,y through the space between the spaced parallel portions 212 of the plunger 268 and through the port 385. In a similar manner, theepressure of fluid acting in chamber 263 on the `piston 251 carrying the release valve 258 is equalized or balanced by the pressure of fluid supplied from the bore 246 through the slot 248 to the right-hand side of vthe piston 251 inthe bore 245.

Ina manner similar to that in the control valve deVice-,S'ofFig 1, the pressure of the fluid supplied to the Vsecondary control pipe 11 is'effective in the chamber' 386 at the left-handy face of the diaphragm follower 244 and thus when the pressure of the uid acting in the chamber 399 to urge the stack of diaphragms in the righthand direction sufficiently balances the fluid pressure force urging the stack of diaphragms in the left-hand direction, the spring 285 becomes effective to return the plunger 298 a certain degree in the right-hand direction. As a result, the supply valve 253 is reseated to cut off the further increase in the pressure in the secondary control pipe 'lll and in the chamber 386. Further movement of the plunger 268 in the righthand direction is thus-stopped so that the suppiy valve 259 remains held in seated position.Y

by the lever 959 on the end of the stem 364 overcomes the tension of the spring 369 and the stem 999 is accordingly yieldingly moved in the righthand direction so that the force applied to the stack of diaphragms urging itin the left-hand direction due to the force of the pressure in theV chamber 398 acting on the left-hand face of the diaphragm 299 does not thereafter increase appreciably because further movement of the diaphragm 299 in the right-hand direction to further compress the spring 3611 and thus increase the force urging the diaphragm stack in the left-hand direction is prevented by the engagement of the follower 399, associated with the diaphragm 299, withthe stop screw-345. c

It will be apparent, therefore, that as the pressure in the primary control pipe 71 and in the chamber 399 continues to increase above the five pounds per square inchr pressure, the biasing force on the stack of'diaphragms caused by the pressure in Vchamber 398 acting on the left-hand face of the diaphragm 299 is maintained and thus alters to some extent the ratio between the primary controlpipe pressure and the secondary control pipe pressure which would ordinarily be in the ratio of the area of the diaphragm 298 to the area of the diaphragm 295. However for very high pressures in the primary control pipe 11a and in the chamber 399 the effect of the biasing force caused by the pressure on the diaphragm 299 is a relatively small percentage. For example, if thearea of the diaphragm follower 244 is to the area of the smallest diaphragm 298 in the ration of three to one and if the primary control pipe lia and the chamber 398 are charged to a pressure of one hundred pounds per square inch, the pressure attained in the secondary control pipe 'H may be of the order of forty pounds per square inch instead of the thirty-three pounds per square inch which would be effected but for the presence of the additional diaphragm 299 and associated lever mechanism,

Since the biasing force exerted on the stack of diaphragms by the pressure of the fluid in chamber 398, on the left-hand face of the diaphragm 299is designed to compensatefor the dierence in the areas of the follower 244 of the largest diaphragm 295 and the area of the smallest diaphragm 299, itvwill be apparent that if an application of the brakesy is initiated at a time that the car or train is traveling at a speed higher than the certain uniform low speed of-fteenfmiles per hour, the biasing force will be greater than that necessary in order to make up for the difference between the'area ofthe follower 294 of diaphragm 295 and the diaphragm 299 or between the follower 294 and the diaphragmZSl'and, consequently,that for the lower pressures in the primary control pipe Tia and in the chamber 398 of the control valve device 9a, the pressure in the secondary control pipe 'l'l may exceed the pressure in the primary control pipe Tia. This is an advantage, if anything, because the brake shoes may be moved intocontact with the car wheels for pressures in the primary control pipe lla which are less than that necessary or required to move the brake shoes into Contact with the car wheels. v y

As the pressure in the primary control pipe 'Ha increases for the various speed ranges of Ythe speed-responsive switch device I9, the effect of the biasing force on the stack of diaphragms and the ultimate effect on secondary control pipe pressure producedby' the pressure of the iluid on the diaphragm 299, decreases in percentage and the ratio of thepressure in the secondary control pipe 'll tothe pressure-iny the primary control pipe 'lla gradually approaches that ratio determined by the ratio of the effective area of the diaphragm 291, diaphragm 299, or the diaphragm 295 to the area of the follower 29d of diaphragm 295, depending upon whether the chamber 391 alone, the chambers 39?V and 399, or the Vchambers 99'?, 399 and 395 are charged with uid under pressure from'the primary control pipe VTia.

K As previously explained, the automaticV reduction in the secondary control pipe pressure, and thus in the brake cylinder pressure, according to the speed of travel of the car or train is always along auniform curve for a given primary control pipe pressure. Thus, assuming that the reduction in the secondary control pipe pressure is taking place along aV curve corresponding to a given primary control pipe pressure and that the operator shifts the operating handle M of Y the brake control device 8 back toward release position to reduce the pressure in the primary control pipe lla, the pressure in the chambers 995, 399 and 99'! of theV control valve device 9o will be higher than that in theY chamber 398 which is connected through the passage ll l to the primary control pipe lla. Consequently the check valves 495, 999 and 99'! are unseated by the higher fluid pressure acting on the inner seated area thereof in passages 335, 339 and 331 respectively, depending upon which of the chambers are charged. Thus the pressure, if any, in

the chambers 395, 399 and 997 is immediatelyk and rapidly reduced to the pressure in the chamber 398 and in the primary control pipe lla, whereupon the check Yvalves 995, 99y and 997 vare reseated by the biasing spring 491i.

Upon the reduction in the pressure in chambers 395,399 and` 391 to correspondrto that in the primary control pipe, the relay valve mechanism29lis operated to release fluid under pressure from the secondary control pipe in the manner similar to that previously described, to proportionately reduce the pressure in the secondary control pipe to a pressure having a ratio to the primary control pipe pressure dependent upon thespeed oftravel of the car.v Thereafter, the 75 reductio'nof secondary control pipe pressure ef- ."fect'ed automatically by the control valve device 9a.isalong'a vuniform curve for the particular pressure to whichV the primary control pipe pressurehas been reduced.

Obviously the brake'control device 8 may be operatedany number of times `to successively decrease the primary control pipe pressure and each Y summarizing, it will be seenr that I Lhave distime the pressure in the chambers 395, SSGand 3,91 or-'in chambers 396 and 391 or in chamber pipe pressure and brake cylinder pressure, l

l ySummary closedherein a brake system of the character described in detail in my copending application 5 Serial No. 741,063, and -including two embodiments of va'control valve'devicewhich is automatically controlledaccordingto the speed of` 'travel of the car or train for causing the degree ofllthe application of the brakes, that is the brakl ing ratio, at the time the application is initially 25.. of. travel `of the car or train at the time the appliyeiectedwto be in accordancewith the speed of VVVicationof the brakes is initiated. T he degree of the application ofthe brakes and thus thebrak- :cylinder pressure.

` ing yratio is determined according to the pressure 30.

to which a primary control pipe is charged under the Lcontrol of the operator, the control valve de- Y vice functioning to proportionately charge a secondary control pipe, which controls the brake It'fwill ralsobe seen thatI have, provided novel control devices in a brake system of the character described, `which function automatically, as

the speed ofthe car or trainrreduces under the application of the brakes,` to reduce the pressure in the secondary control pipe andaccordingly in the brake cylinders in a series ofsteps `or graduations, without however necessitating any change,

' under the controlof the operator, in the primary control pipe pressure. Furthermore, by the pro-- -yisionof suitable timingr means, reductions in the j secondary'controlr pipepressure and accordingly in the Ybrake cylinder pressure take place graduallyand along a uniformv curve for a given primary control pipe pressure.

A[. It will, furthermore, Abe rseen .that in the type of control valve device-as shown in Figs. 2, 3

` .A :by the controlvalve device shown in Fig-1.

Ycontrolpipe pressure and the secondary control and 4,31 have provided two featuresnot possessed One feature ccmlglrises the provision of an additional rdiaphragm to compensate for the difference be- *tweenthe areas of the largest and the'smallest of the fdiaphragms so that up to a certainl pressure-,such as five pounds per square inch, in the secondary control pipe and accordingly in the brake cylinder, the ratio between the primary pipe pressure is rin av substantiallyv one to one Y fratio." vThe purpose of this feature is to move uponthe first few pounds of build-up in the prirapid reduction of the pressure in the'chambers 'between successive diaphragms upon a reduction in; the'primary control pipe pressure, so that rthe subsequent reduction inthe secondary control 'pipe pressure and accordingly in the brake Ycyl-V inder pressure may substantially immediately be The other feature along acurve corresponding to the reduced primary4 controlpipe pressure.

. It'f'should denitely be understood that in practice I contemplate and intend that Vthe brake system in which the control valve devices 9 and 9a arek to `be employed are of the general character shown inV my copending application Serial No. 741,063 and I do not intend therefore that they be restricted in their appliiation to the specific and simplified brake systems shown in Fig. l. Various omissions, additions or modifications may be made in the embodiments of my invention as shown in the drawings Without departing from the spirit of the invention and I do not, therefore, intend to limit the scope of my invention except ras it is necessitatedby the scope of the prior art.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: ,y

l. In a fluid pressure brake system, in combination, means providing a plurality of chambers,

means operative to effect charging of all of said chambers with fluid under pressure upon initiating an application of the brakes, speed-controlled means for varying the pressure in .said chambers f successivelyQand brake control means operative according to the variation of pressure in said chambers for controlling the degree of application of the brakes.

2. In a fluid pressure brake system, in combination, means providing a plurality of chambers, means operative to effect charging of all of said chambers with fluid under pressure upon initiating an application of thelbrakes, speed-controlled means for reducing the pressure in said chambers successively, and brake control means operatively responsive to the reduction in the pressure in said chambers successively for correspondingly reducing thedegree of the brake application.

3. In a fluid pressure brake system for vehicles, means providing a pluralitynof chambers, means operative to cause fluid under pressure to be supplied for charging said chambers when initiating an application of the brakes, means controlled according to the speed of the vehicle for selectivelyfdetermining which chamber or chambers are charged initially upon operation ofsaid last means, and for thereafter reducing the pressure in the, charged chamberssuccessively as the speed of the vehicle reduces, and Vmeans operative according to which chamber or chambers are charged and according to the reduction in the pressure in the Ycharged chambers for effecting corresponding different degrees of application of the brakes.

4. In a fluid pressure brake system for vehicles, means providing a `plurality of chambers, means operative to cause iiuid under pressure to be supplied fcr charging said chambers when initiating an application of the brakes, means controlled according to the speed of the vehicle for selectively determining which chamber or chambers are charged initially upon operation of. said last means, and for thereafter reducing the pressure in the charged chambers successively as the speed of the vehicle reduces, means operative according to which chamber or chambers arecharged and according to the reduction in the pressure in the charged chambers. for effecting corresponding Vdifferent degrees of application of the brakes, and

means for timing the rate of reduction in said rchambers as and when eiected by the speedcontrolled means for causing the variation from one degree of application of the brakes to a lower degree to occur gradually.

5; In a fluid pressure brake system for vehicles, means providing a plurality of chambers, means operative to cause uid under pressure to loe supplied for charging Isaid chambers when initiating an application of the brakes, means controlled according to the speed of the vehicleA for selectively determining which chamber or chambers are charged initially upon operation of said last means, and for thereafter reducing the pressure in the charged chambers successively as the speed of the vehicle reduces, means operative according tovwhich chamber or chambers are charged and according to the reduction in the pressure: inthe c, charged chambers for effecting corresponding different degrees of application of the brakes, and means including a separate chamber connected to each of saidrplurality of chambers, respectively, anda separate choke for each of said plurality of chambers and its connected chamber through which fluid under pressure is vented therefrom, for timing the rate of reduction in said chambers as and when effected kby the speed-controlled means for causing the variation from one degree of application of the brakes to a lower degree to occur gradually.

6. In a fluid pressure brake system forv vehicles, in combination, a control pipe chargeable with fiuid under pressure to initiate application of the brakes, valve means operative to control the supply and release of fluidunder pressure whereby the degree of the application of the brakes is controlled, a plurality of connected movable abutments, of different areas respectively, disposed in spaced coaxial relation, for effecting operation of said valve means, means controlled according to the speed of the vehicle for causing one or more of the spaces between successive abutments to be charged with fluid under pressure from rthe said control pipe and for thereafter reducing the pressure in the charged spaces in succession as the speed of the vehicle reduces, said ValveY means being operated in accordance with the force of the control pipe pressure acting on the abutments to cause corresponding different degrees of applicationj of the brakes to be effected.

7. In a fluid pressure brake system for vehicles, in combination, a brake cylinder, aV control pipe chargeable with fluid under pressure to initiate the application of the brakes, means controlled accordingto the pressure in the control pipe and according to the speed of the vehicle and operative to cause the initial establishment inthe brake cylinder of a pressure having a certain uniform ratio to the control pipe pressure and operative thereafter, as the speed of the vehicle reduces, to cause reduction of the brake cylinder pressure in a plurality of steps without any reduction in the control pipe pressure, and means effective for each step of reduction for controlling the rate of reduction in brake cylinder pressure independently of the speed of the vehicle.

8, In a fluid pressure brake system for vehicles, in combination, a brake cylinder, a control pipe chargeable with fluid under pressure to initiate the application of the brakes, valve means operative to control the pressure in the brake cylinder, a diiferential fluid pressure responsive means subject in opposing relation to the pressure in the control pipe vand a pressure corresponding to that in the brake cylinder for operating said valve means, and means controlled according to the speed of the vehicle for so controlling the area of the fluid pressure responsive ymeans subject to the effective force of the control pipe pressure as to cause operation of the valve means to establish'an initial pressure in the brake cylinder havinga certain uniform ratio to the pressure in the control pipe and thereafter, as the speed of the vehicle reduces, to establish a succession of Vdifferent pressures in the brake cylinder, each pressure in the succession having a'certain uniform ratio to the pressure in the control pipe lower than the ratio of the. immediately preceding pressure.

9, In a fluid pressure brake system for a vehicle, the combination of a primary control pipe chargeable with fluid under pressure to initiate application of the brakes, a secondary control pipe effective to control the degree of application of the brakes according to the pressure to which it is charged, a valve mechanism controlled according to the pressure in the primary control pipe and according to the speed of travel of the vehicle for causing the secondary control pipe to be charged initially to a pressure having a certain uniform ratio to the pressure established in the primary control pipe and for thereafter effecting the reduction of the secondary vcontrol pipe pressure in a plurality of steps without any reduction in the primary control pipe pressure as the speed of the vehicle reduces due to the application of the brakes, and timing means for controlling the rate of thereduction in the secondary controlpipe pressure for each step independently of vehicle speed.

10. In a iiuid pressure brake system for a vehicle, the combination of a primary control pipe chargeable with fluid under pressure to initiate application of the brakes, a secondary control pipe effective to control the degree of application of the brakes according to the pressure to which it is charged, and a valvekmechanismV controlled according to the pressure in ktheprimary control pipe and according to the speed of travel of the vehicle for causing the secondary control pipe to be charged initially to any one of a plurality of pressures having uniform different ratios to the pressure established in the primary control pipe, the particular pressure ratio initially eifective being dependent upon the speed of travel of the Vehicle being within a corresponding one of a plurality of speed Zones at the time the application of the brakes is initiated, said valve mechanism being. operative thereafter as the speed of the vehicle reduces and comes within other and lower 'speed zones for reducing the pressure in the secondary control pipe to others of the plurality of pressures having successively lower uniform ratios to the primary control pipe pressure.

1,1.In a fluid pressure brake system for vehicles, the combination of a primary control pipe chargeable with fluid under pressure to initiate application of the brakes, a secondary control pipe effective to control the degree of application of the brakes in accordance with the degree of fluid pressure established in the secondary control pipe, valve mechanism for controlling the supply and release of fluid under pressure to and fromsaid secondary control pipe, anda differential fluid pressure operated means controlled according to the speed of the vehicle and according tothe pressure in the primary control pipe, for operatingsaid valveV mechanism, upon an application of the brakes being initiated, to initially establish a pressure in the secondary control pipe which bears any one of a plurality of different uniform ratios to the primary control pipe pressure, the. particular ratio effected being determined according to the speed of the vehicle at 

